The present invention relates generally to a heated fluid coupler and more particularly to an improvement over an electrically heated fluid conduit coupler of the type disclosed in U.S. Pat. No. 3,784,785.
2. Description of the Prior Art
In severe climates where subfreezing temperature occur for prolonged periods of time, water pipes and other fluid carriers must be protected from freezing. This problem is particularly prevalent in the farming industry where livestock watering systems are often directly exposed to severe weather without shelter.
In typical livestock watering systems, water is supplied through a water conduit or riser pipe from an underground source located below the frost line to a point of use above the ground. Since the riser pipe must pass through a region of freezing temperatures, both in the ground and in the air, the pipe must be protected at all times from freezing. Further, where water demands are not constant and only occasional use of water occurs, the water in the riser pipe may stay in this pipe for long periods of time, therefore the source temperature of the water may not be relied upon to provide sufficient freezing protection.
The most common method to prevent the riser pipe from freezing is to place an electric heat tape in contact with the pipe. However, this method of artifically heating the riser pipe presents many problems. If the heat tape is exposed to the severe weather conditions, excessive electrical energy will be required to provide the necessary heat to prevent the riser pipe from freezing.
This disadvantage has been overcome by wrapping the riser pipe and heat tape with several layers of insulating material and providing an outside vapor barrier. However, such a method would not be adaptable for use in a stock watering installation because the insulation surrounding the pipe would be subject to being torn or otherwise damaged by the watering livestock. Such damage could result in sections of the heat tape being exposed both to the elements and to the watering stock. If sections of the heat tape should become torn so that the electrical wiring is exposed to the livestock, a very serious health hazard would exist. Further, with the livestock tampering with the heat tape, its effective operation would be impaired, thereby reducing its operational efficiency and allowing the riser pipe to possibly freeze up.
Another disadvantage associated with the use of heat tapes is that, in some instances, their life may be very short and the heat supplied by them to the riser pipe may become irratic and not dependable. Further, in replacing the heat tape, the complete system must be torn down and a new tape wrapped around the pipe. Such a procedure would not be welcomed in severe weather. Also, it is generally not possible to vary the amount of heat supplied by the electrical heat tape when connected to a 110 volt source. Therefore, in very severe weather conditions when a particular heat tape is not performing up to its specifications, the amount of heat produced may not be sufficient to prevent a riser pipe from freezing.
As noted in U.S. Pat. No. 3,120,600, entitled Freezless Water Supply to Cecil W. True, the use of heating tapes coupled with an outside insulation often fails to prevent the freezing of the riser pipe when it is used in soil which contains much moisture. These failures are occasioned by water seeping through the insulation between the vapor barrier and reaching the pipe during periods of thawing. Then when subfreezing temperatures occur, the water acts as a conductor of the heat causing the heat to pass into the surrounding ground instead if being supplied to the riser pipe; thus, resulting in freezing of the riser pipe.
Furthermore, in the wrapping of heat tapes around the riser pipe, if the tape would touch, overlap or cross over itself, it would tend to overheat and subsequently burn out. Also, in cold weather, heat tapes typically become stiff and difficult to uncoil; thereby, presenting additional problems if a tape must be replaced in subfreezing weather.
Also, because of servicing requirements of heat tapes, it would be impractical to completely bury the power cable underground, thereby necessitating some type of shielding to be placed around the power cable to prevent the watering livestock from interfering and damaging it and themselves.
Another approach was developed by Woodford Manufacturing Company, Des Moines, Iowa entitled Thermaline. Thermaline combines a riser pipe with an operation pipe positioned inside it and an electrical heating element passing down into the operation pipe. Heating occurs through a process of conduction from the heating element to the water in the operation pipe and finally to the water in the riser pipe. The heating element passes through the top of the apparatus to be connected to a 110 volt source. Because of the location of the heating element, an elbow is connected to the top of the apparatus to the riser pipe providing a water tap for external use. The complete Thermaline apparatus is enclosed in insulation with an outer casing on the outside.
The Thermaline unit, while well adapted for its intended use as a water line heater for a mobil home, would present several problems if employed as a livestock water line heater. Because of the placement of the heating element, the power cord from the 110 volt supply would be external and would have to be shielded from the watering livestock. Also, because of the heating element position and the use of the elbow to conduct the water flow, multiple connections to the unit from the water using devices would be difficult if not impossible while still retaining weather protection. Further, multiple units could not easily be used from a single water source with only one water line tap on the main water line and employing only one heating element. Furthermore, with the positioning of the heating element directly in the water supply, additional shielding on the heating elment would be required to insure against its gradual breakdown from a chemical reaction with the water and presenting a very serious electrical shock hazard.
For the above described reasons and considerations, the present methods are not adequate to solve the problems encountered in supplying a source of fresh water in subfreezing temperatures to unsheltered livestock watering installations.